Um. Service manual or owners manual? If you're lucky, the amount of oil to put in will be stamped on the side of the case by the oil fill hole.
Seems odd that you drained the oil without knowing what type/amount to put back in. You can use cheap 10w30 or 10w40 (withOUT friction modifiers, very important!), ATF type F, gear oil, or a wet clutch specific motorcycle transmission oil. The yamalube will work fine, yes.